1. Field of the Invention
The present invention relates to a jaw movement simulator in which an upper jaw model patterned after an upper jaw and a lower jaw model patterned after a lower jaw are mounted, and the lower jaw model is relatively moved with respect to the upper jaw model, a jaw movement simulation system for causing the jaw movement simulator to reproduce a movement of the jaw of a test subject in accordance with data obtained through imaging a movement of the jaw of the test subject, and a jaw movement simulation method using the jaw movement simulation system.
2. Description of the Related Art
In the field of dentistry, and more particularly in the field of the dental prosthesis, there is performed such an investigation that models patterned after the upper teeth (upper jaw) and the lower teeth (lower jaw) are formed (such models are referred to as the upper jaw model and the lower jaw model, respectively), and those models are mounted on an articulator device for a simulation of a movement of the jaw, so that the state of occlusion of the upper teeth and the lower teeth is investigated. Thus, there is produced a dental prosthesis (e.g. denture) having a suitable shape according to the state of occlusion.
FIG. 1 is a typical illustration of part of the jaw of the human body.
An upper jaw 2 and a lower jaw 3 are coupled with each other taking a condyle 4 as a joint. The lower jaw 3 is able to perform not only a simple motion of opening and closing one's mouth upward and downward with respect to the upper jaw 2, but also various motions such as moving it back and forth and left and right with respect to the upper jaw 2, and opening one's mouth at a slant. The condyle 4 serves as a complicated joint capable of implementing those various motions. A shape of the condyle and its movement are varied for each person.
Hitherto, as articulators for observing the state of occlusion of the upper jaw model and the lower jaw model mounted thereon, there have been proposed various articulators, for example, a plane line articulator capable of performing only a simple motion of opening and closing for one's mouth; a full adjusted articulator in which a skeleton of the upper jaw 2 and the lower jaw 3 including the condyle 4 is modeled, and a portion corresponding to the condyle of the human body is given with the same freedom as that of the condyle of the human body; and an articulator provided with the mid freedom as compared to that of the condyle of the human body. It is possible to reproduce the more similar motion to that of the human's jaw with larger freedom. However, an adjustment for implementing a high reproduction of movement is a very hard task. Usually, such an adjustment is performed in accordance with intuition of dentists and dental technicians. This often brings about the reproduction of an average movement of jaws of a large number of persons, and thus it is very difficult to exactly reproduce a movement of the jaw of the respective person. Thus, even if such an articulator is used to reproduce a movement of the jaw, there will remain a part which does not match a movement of the jaw of the respective person. Accordingly, on the occasion of making a dental prosthesis, it is obliged to draw on dentist's or dental technician's experience.
It may happen that something wrong in a movement of the jaw or in an occlusion of teeth causes symptoms of stiff shoulders, headache and giddiness to be developed. Recently, it becomes a subject how to grasp that those symptoms are caused by a movement of the jaw, etc. In order to solve this subject, there is a need to provide an apparatus capable of exactly reproducing a movement of the jaw of an individual.